Question: Amtrak operates which train service?
Paraphrase: Amtrak works which train administration?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q23239 wdt:P121 ?obj . ?obj wdt:P31 wd:Q15141321 } 
Answer: Auto Train, Acela, Keystone Service, Carl Sandburg, Illinois Zephyr, Saluki